Water-cooled mercury-vapor arc lamp



March 11, 1930. w. T. ANDERSON, JR

WATER COOLED MERCURY VAPOR mo LAMP Filed May 13, 1927 INVENTOR ,Jz, O W

A'Y T ORNEY Patented Mar. 11, 1930 UNITED STATES PATENT OFFICE l I WILLIAM '1. ANDERSON, JR., OF NEWARK, NEW JERSEY, ASSIGNOR TO HANOVIA CHEMICAL AND MANUFACTURING COMPANY, OF NEWARK, NEW JERSEY, A COR- PORATION OF NEW JERSEY WATER-COOLED MERCURY-VAPOR ARC LAMP Application filed May 13, 1927. Serial No. 190,974;

This invention relates to improvements in the construction and operation of mercury vapor arc lamps and more particularly to such types as use tubes made of quartz and emplo ed for therapeutical uses.

Such lamps generate heat to a considerable degree and necessitate the rovision of some means to carry off supera undant heat for reasons that are well known.

Up to the present time water-cooled mercury vapor lamps have been constructed so that the receptacle containing the luminous arc consisted of a straight tube disposed in either a horizontal or vertical position, or with an intermediate evacuted or air-filled space separating the tube from the water jacket to prevent a too great cooling of the arc.

Occasionally the arc tube is made in the 2 form of an inverted U wholly encased within an evacuated or gas filled chamber, serving the same purpose.

This second arrangement possesses the advantage that a greater length of arc is contained within a smaller space and correspondingly greater unit intensity is secured.

A certain disadvantage of this method is in the fact that those parts of the arc tube nearest the wall of the jacket are cooled to a greater extent than the parts more remote, causing more rapid deterioration of the wall of the arc tube where the cooling is insufiicient.

It is therefore the main object of the present invention to provide a quartz envelope shaped in conformity to the are tube so as to maintain an approximately equal distance between the walls of the tube and envelope at all points.

A further feature is in the provision of an envelope filled with any desired gas whereby the cooling effect of the outer circulating water may be secured by varying the nature of the gas and also its pressure.

These and other advantages are accomplished by the novel construction and arrangement of parts hereinafter described and shown in the accompanying drawing, forming part hereof, and in which Figure 1 is a front elevational view of a preferred form of lamp partially broken away and partially in section to show the construction.

Figure 2 is a sectional view taken substantially on line 22 of Figure 1.

Figure 3 is a to plan View of the arc tube and envelope in etail.

In the improved lamp shown, the are tube consists of an upstanding hollow loop 5, essentially in the form of an inverted U its lower portions 6 converging and being blended by curved right angular bends 7 into rearwardly reaching, parallel extensions 8 partially filled with mercury and into which enter conductors 9 from a source of suitable electric current, this structure being well known.

Fused or otherwise hermetically fixed to the walls of the arc tube 56, just above the bent portions 7 are the ends of a circumjacent quartz envelope 10 presenting a sealed space 11 of substantially uniform thickness, the same to be filled with any preferred gas, such as air, oxygen, nitrogen, argon, helium, hydrogen, ammonia or carbon-dioxide.

Circumambient the-envelope and exposed parts of the arc tube is a jacket 14 enclosing a chamber 15 and shaped to extend to the rear enclosing the tube extensions 8, this jacket being provided with inlet and outlet connections for attachment to a water supply source and drain respectively.

The front of the jacket 14 is closed by a transparent plate 16, preferably of quartz glass, to permit the light from the mercury arc to show outwardly and a frame 17 is provided as shown.

It will be understood that the cooling effect of water circulating in the jacket space 15 will be varied in accordance with the nature of the gas contained in the envelope space 11 and also by the gaseous pressure within the envelope, and the electrical characteristics of the arc will obviously vary with the thermal conductivity of the gas or gaseous mixture employed within the envelope.

In the structure described the heat dis tribution between the arc tube 5 and the cooling water in the jacket 14 is such that devitrification of the quartz of the arc tube is reatly delayed, resulting in greatly prolongmg its usefulness over types hitherto used.

t is to be understood that the design and construction disclosed is suitable for operation on direct or unidirectional current and that the principles involved may be readily applied to mercury vapor arc lamps constructed with branched arc tubes, using three or more electrodes and operated on direct or alternating current.

Although I have described my improvements with considerable detail and with respect to certain particular forms of my invention, I do not desire to be limited to such details since many changes and modifications may well be made without departing from the spirit and scope of my invention in its broadest aspect.

Having thus described my invcntion, What I claim as new and desire to secure by Letters Patent, is

1. A mercury va or arc lamp comprising a quartz arc tube'in t e form of a loop and having rearward extensions at right angles from its lower end, a que rtz envelope enclosing the loop portion of said tube, said envelope being sha ed in conformity with and equally spaced iiom said tube, a jacket surrounding said envelope and tube, and means in said jacket to permit a circulation of water therethrou h.

2. mercury vapor arc lamp comprising a quartz arc tube in the form of a loop and having rearward extensions at right angles from its lower end, a quartz envelope enclosing the loo portion of said tube, said envelope being s aped in conformity with and equally spaced from said tube, a gas in said envelope, and a jacket surrounding said envelope and tube, and means in said -acket to permit a circulation of water therct rough.

3. A mercury vapor arc lamp comprising a quartz arc tube in the form of a loop and having rearward extensions at right angles from its lower end, a quartz envelope enclosing the loop portion of said tube, said envelope being shaped in conformity with and equally spaced from said tube, a jacket surrounding said envelope and tube, means in said jacket to permit a circulation of water therethrough, and a lens in said jacket through which light from said lamp may pass.

This specification signed and witnessed this 6th day of Ma 1927.

WM T. ANDERSON, JR. 

